Binding Sites Number and Binding Affinity of MoAb 62 to CHO Cells and to Resting Platelets in the Absence or Presence of Echistatin and Its Analogs
| Disintegrin . | A5 Cells . | VNRC3 Cells . | Platelets . |
|---|---|---|---|
| None | 15,010 ± 2,600 | 14,430 ± 1,200 | 1,690 ± 200 |
| 2.7 ± 0.4 nmol/L | 3.5 ± 0.9 nmol/L | 22.0 ± 5.0 nmol/L | |
| Echistatin | 26,930 ± 1,080 | 28,650 ± 2,600 | 17,180 ± 2,420 |
| 3.0 ± 0.4 nmol/L | 4.0 ± 1.0 nmol/L | 22.0 ± 3.0 nmol/L | |
| Echistatin D27W | 23,770 ± 1,470 | 19,770 ± 930 | 17,510 ± 3,150 |
| 2.5 ± 0.4 nmol/L | 2.9 ± 0.4 nmol/L | 22.0 ± 7.0 nmol/L | |
| Echistatin 1-41 | 16,300 ± 3,100 | 16,280 ± 1,110 | 8,084 ± 1,500 |
| 2.6 ± 0.5 nmol/L | 3.4 ± 1.0 nmol/L | 45.0 ± 6.0 nmol/L | |
| Echistatin R24A | 14,750 ± 1,500 | 15,160 ± 1,010 | ND |
| 3.0 ± 0.4 nmol/L | 3.1 ± 0.2 nmol/L |
| Disintegrin . | A5 Cells . | VNRC3 Cells . | Platelets . |
|---|---|---|---|
| None | 15,010 ± 2,600 | 14,430 ± 1,200 | 1,690 ± 200 |
| 2.7 ± 0.4 nmol/L | 3.5 ± 0.9 nmol/L | 22.0 ± 5.0 nmol/L | |
| Echistatin | 26,930 ± 1,080 | 28,650 ± 2,600 | 17,180 ± 2,420 |
| 3.0 ± 0.4 nmol/L | 4.0 ± 1.0 nmol/L | 22.0 ± 3.0 nmol/L | |
| Echistatin D27W | 23,770 ± 1,470 | 19,770 ± 930 | 17,510 ± 3,150 |
| 2.5 ± 0.4 nmol/L | 2.9 ± 0.4 nmol/L | 22.0 ± 7.0 nmol/L | |
| Echistatin 1-41 | 16,300 ± 3,100 | 16,280 ± 1,110 | 8,084 ± 1,500 |
| 2.6 ± 0.5 nmol/L | 3.4 ± 1.0 nmol/L | 45.0 ± 6.0 nmol/L | |
| Echistatin R24A | 14,750 ± 1,500 | 15,160 ± 1,010 | ND |
| 3.0 ± 0.4 nmol/L | 3.1 ± 0.2 nmol/L |
The number of binding sites and binding affinity for MoAb 62 were estimated in absence or presence of disintegrin at a concentration of 100 nmol/L by Scatchard analysis of the 125I binding data from three experiments. The values correspond to the mean and standard deviation from three independent experiments. Binding affinity are expressed in nanomoles per liter. P = .002, .0076, .616, and .894 when comparing A5 cells without distintegrins and A5 cells with wild-type echistatin, D27W echistatin, echistatin 1-41, and R24A echistatin, respectively; P = .040 when comparing A5 cells with wild-type echistatin and A5 cells with D27W echistatin; P = .0011, .0039, .124, and .468 when comparing VNRC3 cells without disintegrins and VNRC3 cells with wild-type echistatin, D27W echistatin, echistatin 1-41, and R24A echistatin, respectively; P = .0056 when comparing VNRC3 cells with wild-type echistatin and VNRC3 cells with D27W echistatin; P = .0004, .001, and .002 when comparing resting platelets without disintegrins and resting platelets with wild-type echistatin, D27W echistatin, and echistatin 1-41, respectively.